Clinicopathological features, response patterns, outcomes and BRAF status in patients with advanced acral melanoma: a preliminary Peruvian study.

Background: Globally, acral melanoma (AM) is underrepresented in most clinical trials, being predominant in Caucasian populations. Latin America is a niche that needs to be explored. Therefore, this study aimed to determine the clinical features, response patterns, outcomes and v-raf murine sarcoma viral oncogene homolog B1 (BRAF) status in Peruvian patients with advanced AM.

Methods: We retrospectively reviewed the medical records of 19 patients with advanced AM who received immunotherapy (IO) in first- or subsequent-line therapy. The samples were analysed, and their mutational state was performed by deoxyribonucleic acid sequencing, focusing primarily on the most frequently mutated gene, BRAF. Descriptive statistics were used to assess the baseline characteristics. Overall survival was estimated using the Kaplan-Meier method.

Results: The median age was 64 years and 63.2% were men. Plantar was the site most frequently affected (84.2%). The most frequent stage was stage III (68.4%), with 26.4% receiving adjuvant therapy. The majority of cases exhibited a Breslow thickness of >4 mm (52%), a Clark level of IV/V (89.4%), and all patients presented ulceration and a high range of mitosis. During follow-up, all patients experienced recurrent advanced disease, with 52.6% developing visceral metastasis. Patients who received IO as first or subsequent line had an overall response rate (ORR) of 33.3%, and those who received it as first-line therapy had an ORR of 40%. Twenty-one percent of the patients harbored BRAF V6000E mutation and, showing an ORR of 50% compared to wild-type individuals (44.4%) after the first line of treatment.

Conclusion: Our preliminary study reported that AM has poor clinico-pathological features and response rates to IO in Peruvian patients. However, those who received IO as a first-line treatment or harbored the BRAF mutation appeared to have a slightly better response than wild-type patients.